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862500.9823Marine viruses: truth or dare. Over the past two decades, marine virology has progressed from a curiosity to an intensely studied topic of critical importance to oceanography. At concentrations of approximately 10 million viruses per milliliter of surface seawater, viruses are the most abundant biological entities in the oceans. The majority of these viruses are phages (viruses that infect bacteria). Through lysing their bacterial hosts, marine phages control bacterial abundance, affect community composition, and impact global biogeochemical cycles. In addition, phages influence their hosts through selection for resistance, horizontal gene transfer, and manipulation of bacterial metabolism. Recent work has also demonstrated that marine phages are extremely diverse and can carry a variety of auxiliary metabolic genes encoding critical ecological functions. This review is structured as a scientific "truth or dare," revealing several well-established "truths" about marine viruses and presenting a few "dares" for the research community to undertake in future studies.201222457982
917310.9809Bacterial defences: mechanisms, evolution and antimicrobial resistance. Throughout their evolutionary history, bacteria have faced diverse threats from other microorganisms, including competing bacteria, bacteriophages and predators. In response to these threats, they have evolved sophisticated defence mechanisms that today also protect bacteria against antibiotics and other therapies. In this Review, we explore the protective strategies of bacteria, including the mechanisms, evolution and clinical implications of these ancient defences. We also review the countermeasures that attackers have evolved to overcome bacterial defences. We argue that understanding how bacteria defend themselves in nature is important for the development of new therapies and for minimizing resistance evolution.202337095190
958320.9806Bacteriophages presence in nature and their role in the natural selection of bacterial populations. Phages are the obligate parasite of bacteria and have complex interactions with their hosts. Phages can live in, modify, and shape bacterial communities by bringing about changes in their abundance, diversity, physiology, and virulence. In addition, phages mediate lateral gene transfer, modify host metabolism and reallocate bacterially-derived biochemical compounds through cell lysis, thus playing an important role in ecosystem. Phages coexist and coevolve with bacteria and have developed several antidefense mechanisms in response to bacterial defense strategies against them. Phages owe their existence to their bacterial hosts, therefore they bring about alterations in their host genomes by transferring resistance genes and genes encoding toxins in order to improve the fitness of the hosts. Application of phages in biotechnology, environment, agriculture and medicines demands a deep insight into the myriad of phage-bacteria interactions. However, to understand their complex interactions, we need to know how unique phages are to their bacterial hosts and how they exert a selective pressure on the microbial communities in nature. Consequently, the present review focuses on phage biology with respect to natural selection of bacterial populations.202033170167
958030.9806Antibiotic resistance in bacterial communities. Bacteria are single-celled organisms, but the survival of microbial communities relies on complex dynamics at the molecular, cellular, and ecosystem scales. Antibiotic resistance, in particular, is not just a property of individual bacteria or even single-strain populations, but depends heavily on the community context. Collective community dynamics can lead to counterintuitive eco-evolutionary effects like survival of less resistant bacterial populations, slowing of resistance evolution, or population collapse, yet these surprising behaviors are often captured by simple mathematical models. In this review, we highlight recent progress - in many cases, advances driven by elegant combinations of quantitative experiments and theoretical models - in understanding how interactions between bacteria and with the environment affect antibiotic resistance, from single-species populations to multispecies communities embedded in an ecosystem.202337054512
836140.9805Functional potential and evolutionary response to long-term heat selection of bacterial associates of coral photosymbionts. Symbiotic microorganisms are crucial for the survival of corals and their resistance to coral bleaching in the face of climate change. However, the impact of microbe-microbe interactions on coral functioning is mostly unknown but could be essential factors for coral adaption to future climates. Here, we investigated interactions between cultured dinoflagellates of the Symbiodiniaceae family, essential photosymbionts of corals, and associated bacteria. By assessing the genomic potential of 49 bacteria, we found that they are likely beneficial for Symbiodiniaceae, through the production of B vitamins and antioxidants. Additionally, bacterial genes involved in host-symbiont interactions, such as secretion systems, accumulated mutations following long-term exposure to heat, suggesting symbiotic interactions may change under climate change. This highlights the importance of microbe-microbe interactions in coral functioning.202337909753
832850.9804The Diverse Impacts of Phage Morons on Bacterial Fitness and Virulence. The viruses that infect bacteria, known as phages, are the most abundant biological entity on earth. They play critical roles in controlling bacterial populations through phage-mediated killing, as well as through formation of bacterial lysogens. In this form, the survival of the phage depends on the survival of the bacterial host in which it resides. Thus, it is advantageous for phages to encode genes that contribute to bacterial fitness and expand the environmental niche. In many cases, these fitness factors also make the bacteria better able to survive in human infections and are thereby considered pathogenesis or virulence factors. The genes that encode these fitness factors, known as "morons," have been shown to increase bacterial fitness through a wide range of mechanisms and play important roles in bacterial diseases. This review outlines the benefits provided by phage morons in various aspects of bacterial life, including phage and antibiotic resistance, motility, adhesion and quorum sensing.201930635074
937160.9804Coevolutionary history of predation constrains the evolvability of antibiotic resistance in prey bacteria. Understanding how the historical contingency of biotic interactions shapes the evolvability of bacterial populations is imperative for the predictability of the eco-evolutionary dynamics of microbial communities. While microbial predators like Myxococcus xanthus influence the frequency of antibiotic-resistant bacteria in nature, the effect of adaptation to the presence of predators on the evolvability of prey bacteria to future stressors is unclear. Hence, to understand the influence of the coevolutionary history of predation on the evolvability of antibiotic resistance, we propagated variants of E. coli, pre-adapted to distinct biotic and abiotic conditions, in gradually increasing concentrations of antibiotics. We show that pre-adaptation to predators limits the evolution of a high degree of antibiotic resistance. Moreover, lower degree of resistance in the evolved strains also incurs reduced fitness costs while preserving their ancestral ability to resist predation. Together, we demonstrate that the history of biotic interactions can strongly influence the evolvability of bacteria.202540461734
972770.9803Metal Toxicity and Resistance in Plants and Microorganisms in Terrestrial Ecosystems. Metals are major abiotic stressors of many organisms, but their toxicity in plants is not as studied as in microorganisms and animals. Likewise, research in plant responses to metal contamination is sketchy. Candidate genes associated with metal resistance in plants have been recently discovered and characterized. Some mechanisms of plant adaptation to metal stressors have been now decrypted. New knowledge on microbial reaction to metal contamination and the relationship between bacterial, archaeal, and fungal resistance to metals has broadened our understanding of metal homeostasis in living organisms. Recent reviews on metal toxicity and resistance mechanisms focused only on the role of transcriptomics, proteomics, metabolomics, and ionomics. This review is a critical analysis of key findings on physiological and genetic processes in plants and microorganisms in responses to soil metal contaminations.202030725190
871480.9803Tales from the tomb: the microbial ecology of exposed rock surfaces. Although a broad diversity of eukaryotic and bacterial taxa reside on rock surfaces where they can influence the weathering of rocks and minerals, these communities and their contributions to mineral weathering remain poorly resolved. To build a more comprehensive understanding of the diversity, ecology and potential functional attributes of microbial communities living on rock, we sampled 149 tombstones across three continents and analysed their bacterial and eukaryotic communities via marker gene and shotgun metagenomic sequencing. We found that geographic location and climate were important factors structuring the composition of these communities. Moreover, the tombstone-associated microbial communities varied as a function of rock type, with granite and limestone tombstones from the same cemeteries harbouring taxonomically distinct microbial communities. The granite and limestone-associated communities also had distinct functional attributes, with granite-associated bacteria having more genes linked to acid tolerance and chemotaxis, while bacteria on limestone were more likely to be lichen associated and have genes involved in photosynthesis and radiation resistance. Together these results indicate that rock-dwelling microbes exhibit adaptations to survive the stresses of the rock surface, differ based on location, climate and rock type, and seem pre-disposed to different ecological strategies (symbiotic versus free-living lifestyles) depending on the rock type.201829235707
947890.9803General principles of antibiotic resistance in bacteria. Given the impact of antibiotic resistance on human health, its study is of great interest from a clinical view- point. In addition, antibiotic resistance is one of the few examples of evolution that can be studied in real time. Knowing the general principles involved in the acquisition of antibiotic resistance is therefore of interest to clinicians, evolutionary biologists and ecologists. The origin of antibiotic resistance genes now possessed by human pathogens can be traced back to environmental microorganisms. Consequently, a full understanding of the evolution of antibiotic resistance requires the study of natural environments as well as clinical ecosystems. Updated information on the evolutionary mechanisms behind resistance, indicates that ecological connectivity, founder effect and fitness costs are important bottle- necks that modulate the transfer of resistance from environmental microorganisms to pathogens.201424847651
8422100.9801Slightly beneficial genes are retained by bacteria evolving DNA uptake despite selfish elements. Horizontal gene transfer (HGT) and gene loss result in rapid changes in the gene content of bacteria. While HGT aids bacteria to adapt to new environments, it also carries risks such as selfish genetic elements (SGEs). Here, we use modelling to study how HGT of slightly beneficial genes impacts growth rates of bacterial populations, and if bacterial collectives can evolve to take up DNA despite selfish elements. We find four classes of slightly beneficial genes: indispensable, enrichable, rescuable, and unrescuable genes. Rescuable genes - genes with small fitness benefits that are lost from the population without HGT - can be collectively retained by a community that engages in costly HGT. While this 'gene-sharing' cannot evolve in well-mixed cultures, it does evolve in a spatial population like a biofilm. Despite enabling infection by harmful SGEs, the uptake of foreign DNA is evolutionarily maintained by the hosts, explaining the coexistence of bacteria and SGEs.202032432548
6449110.9801Microbial regulation of natural antibiotic resistance: Understanding the protist-bacteria interactions for evolution of soil resistome. The emergence, evolution and spread of antibiotic resistance genes (ARGs) in the environment represent a global threat to human health. Our knowledge of antibiotic resistance in human-impacted ecosystems is rapidly growing with antibiotic use, organic fertilization and wastewater irrigation identified as key selection pressures. However, the importance of biological interactions, especially predation and competition, as a potential driver of antibiotic resistance in the natural environment with limited anthropogenic disturbance remains largely overlooked. Stress-affected bacteria develop resistance to maximize competition and survival, and similarly bacteria may develop resistance to fight stress under the predation pressure of protists, an essential component of the soil microbiome. In this article, we summarized the major findings for the prevalence of natural ARGs on our planet and discussed the potential selection pressures driving the evolution and development of antibiotic resistance in natural settings. This is the first article that reviewed the potential links between protists and the antibiotic resistance of bacteria, and highlighted the importance of predation by protists as a crucial selection pressure of antibiotic resistance in the absence of anthropogenic disturbance. We conclude that an improved ecological understanding of the protists-bacteria interactions and other biological relationships would greatly expand our ability to predict and mitigate the environmental antibiotic resistance under the context of global change.202031818598
9193120.9801The bacteriophage decides own tracks: When they are with or against the bacteria. Bacteriophages, bacteria-infecting viruses, are considered by many researchers a promising solution for antimicrobial resistance. On the other hand, some phages have shown contribution to bacterial resistance phenomenon by transducing antimicrobial resistance genes to their bacterial hosts. Contradictory consequences of infections are correlated to different phage lifecycles. Out of four known lifecycles, lysogenic and lytic pathways have been riddles since the uncontrolled conversion between them could negatively affect the intended use of phages. However, phages still can be engineered for applications against bacterial and viral infections to ensure high efficiency. This review highlights two main aspects: (1) the different lifecycles as well as the different factors that affect lytic-lysogenic switch are discussed, including the intracellular and molecular factors control this decision. In addition, different models which describe the effect of phages on the ecosystem are compared, besides the approaches to study the switch. (2) An overview on the contribution of the phage in the evolution of the bacteria, instead of eating them, as a consequence of different mode of actions. As well, how phage display has helped in restricting phage cheating and how it could open new gates for immunization and pandemics control will be tacked.202134841341
9581130.9800Lateral gene transfer, bacterial genome evolution, and the Anthropocene. Lateral gene transfer (LGT) has significantly influenced bacterial evolution since the origins of life. It helped bacteria generate flexible, mosaic genomes and enables individual cells to rapidly acquire adaptive phenotypes. In turn, this allowed bacteria to mount strong defenses against human attempts to control their growth. The widespread dissemination of genes conferring resistance to antimicrobial agents has precipitated a crisis for modern medicine. Our actions can promote increased rates of LGT and also provide selective forces to fix such events in bacterial populations. For instance, the use of selective agents induces the bacterial SOS response, which stimulates LGT. We create hotspots for lateral transfer, such as wastewater systems, hospitals, and animal production facilities. Conduits of gene transfer between humans and animals ensure rapid dissemination of recent transfer events, as does modern transport and globalization. As resistance to antibacterial compounds becomes universal, there is likely to be increasing selection pressure for phenotypes with adverse consequences for human welfare, such as enhanced virulence, pathogenicity, and transmission. Improved understanding of the ecology of LGT could help us devise strategies to control this fundamental evolutionary process.201727706829
6439140.9800A review: Marine aquaculture impacts marine microbial communities. Marine aquaculture is key for protein production but disrupts marine ecosystems by releasing excess feed and pharmaceuticals, thus affecting marine microbes. Though vital, its environmental impact often remains overlooked. This article delves into mariculture's effects on marine microbes, including bacteria, fungi, viruses, and antibiotic-resistance genes in seawater and sediments. It highlights how different mariculture practices-open, pond, and cage culture-affect these microbial communities. Mariculture's release of nutrients, antibiotics, and heavy metals alters the microbial composition, diversity, and functions. Integrated multi-trophic aquaculture, a promising sustainable approach, is still developing and needs refinement. A deep understanding of mariculture's impact on microbial ecosystems is crucial to minimize pollution and foster sustainable practices, paving the way for the industry's sustainable advancement.202438919720
9578150.9799Type III secretion systems in symbiotic adaptation of pathogenic and non-pathogenic bacteria. The emergence of multi-drug resistance and bacteria with increased virulence is a familiar refrain to the contemporary microbiologist. Although intense research over the past decade has ascribed much molecular detail to these processes, more esoteric questions remain: for example, why are some bacteria evolving increased virulence towards humans, what are the genes underpinning this virulence potential and what are the selective pressures that favor these traits? A holistic approach that considers the organismal biology of bacteria with their diverse hosts seems appropriate to begin to tackle such issues. As it happens, the type III secretion system is turning out to be a central player in the adaptation of both parasites and mutualists to diverse hosts. With this in mind, human interventions in agriculture, animal husbandry and even drug discovery that could influence the selection of bacteria with improved type III secretion system function should be critically appraised.200919217298
8362160.9798Lifestyle evolution in symbiotic bacteria: insights from genomics. Bacteria that live only in eukaryotic cells and tissues, including chronic pathogens and mutualistic bacteriocyte associates, often possess a distinctive set of genomic traits, including reduced genome size, biased nucleotide base composition and fast polypeptide evolution. These phylogenetically diverse bacteria have lost certain functional categories of genes, including DNA repair genes, which affect mutational patterns. However, pathogens and mutualistic symbionts retain loci that underlie their unique interaction types, such as genes enabling nutrient provisioning by mutualistic bacteria-inhabiting animals. Recent genomic studies suggest that many of these bacteria are irreversibly specialized, precluding shifts between pathogenesis and mutualism.200010884696
8327170.9798'Big things in small packages: the genetics of filamentous phage and effects on fitness of their host'. This review synthesizes recent and past observations on filamentous phages and describes how these phages contribute to host phentoypes. For example, the CTXφ phage of Vibrio cholerae encodes the cholera toxin genes, responsible for causing the epidemic disease, cholera. The CTXφ phage can transduce non-toxigenic strains, converting them into toxigenic strains, contributing to the emergence of new pathogenic strains. Other effects of filamentous phage include horizontal gene transfer, biofilm development, motility, metal resistance and the formation of host morphotypic variants, important for the biofilm stress resistance. These phages infect a wide range of Gram-negative bacteria, including deep-sea, pressure-adapted bacteria. Many filamentous phages integrate into the host genome as prophage. In some cases, filamentous phages encode their own integrase genes to facilitate this process, while others rely on host-encoded genes. These differences are mediated by different sets of 'core' and 'accessory' genes, with the latter group accounting for some of the mechanisms that alter the host behaviours in unique ways. It is increasingly clear that despite their relatively small genomes, these phages exert signficant influence on their hosts and ultimately alter the fitness and other behaviours of their hosts.201525670735
9589180.9798Phage Therapy: Going Temperate? Strictly lytic phages have been consensually preferred for phage therapy purposes. In contrast, temperate phages have been avoided due to an inherent capacity to mediate transfer of genes between bacteria by specialized transduction - an event that may increase bacterial virulence, for example, by promoting antibiotic resistance. Now, advances in sequencing technologies and synthetic biology are providing new opportunities to explore the use of temperate phages for therapy against bacterial infections. By doing so we can considerably expand our armamentarium against the escalating threat of antibiotic-resistant bacteria.201930466900
6445190.9798Microplastics: Disseminators of antibiotic resistance genes and pathogenic bacteria. Microplastics (MPs) are emerging pollutants that linger in the air, water, and land. Beyond their physical and chemical risks, there is growing evidence that MPs contribute to the worldwide antimicrobial resistance (AMR) dilemma by acting as carriers of harmful microbes and antibiotic resistance genes (ARGs). Despite an increase in research, the available literature is dispersed, and the part that MPs play in influencing microbial populations and fostering resistance is still not well understood. This review summarizes current research on how MPs contribute to the spread of antibiotic resistance. We concentrated on the ways in which MPs support horizontal gene transfer (HGT) processes such as conjugation, transformation, and transduction, assist biofilm development, and offer surfaces for microbial colonization. Evidence from a variety of settings suggests that MPs serve as vectors for opportunistic pathogens, such as the ESKAPE group, and ARGs, increasing the survival and movement of resistance determinants in ecosystems. Through the consolidation of current developments, this review emphasizes MPs as active resistance vectors instead of passive pollutants. We also point out important limitations, such as the lack of standardized procedures, inadequate risk assessment frameworks, and the absence of real-world exposure research. It is imperative that these issues be approached from a One Health standpoint in order to reduce the risks of both plastic pollution and antibiotic resistance.202541056605